Oxygen is essential for sustaining of all aerobic living matter which is inclusive of essentially all known forms of animal and plant life. In humans and other forms of animal life, generally the respiratory cycle comprises breathing in of oxygen which is absorbed in the lungs and distributed accordingly in the blood, to various organs and is eventually “used” up, i.e. exchanged or converted to carbon dioxide by various body interactions and exhaled from the lungs primarily as carbon dioxide or other expiratory gases.
On the other hand, plant life is dependent upon carbon dioxide and takes it in where, through photosynthesis, it is metabolized or used by the plant in various processes and is eventually converted and released into the atmosphere as oxygen.
This life cycle is essential to the living planet and all living species is well documented and will not be further addressed in this specification.
However, each of these gasses has downsides as well. Oxygen participates in or causes the degradation of organic materials to which it has been exposed. This is particularly true with perishable organic materials such as fruits, vegetables, grains, meat products, processed foods, powdered products such as flour, pharmaceuticals, and the like which may be in an atmosphere maintained at ambient temperatures or above. In other words, the lowering of temperatures and lessening or removal of available oxygen content contributes to lengthening the useful life of such materials. Refrigeration is a common mechanism used to extend useful life of perishable goods. Unfortunately, refrigeration also utilizes substantial amounts of energy to maintain suitably low temperatures to achieve desired results.
Oxygen perishable items from the time of gathering or production, whether by reaping, picking, digging, cutting, collecting, butchering, processing, cooking, displaying, packaging or any other means, where such items are present in an open environment for a period of time, are subject to being exposed to oxygen. Surrounding environments are those present when gathering perishables by any of the above methods as well as loading, transporting, warehousing, manufacturing or processing, packaging in crates or other shipping containers for overland or sea transport, packaging or sealing in containers for sale, refrigerated shipping or storage, cooling and sectioning of butchered animals and the like. An open environment is also inclusive of enclosed or semi-enclosed spaces such as found in display counters holding fruits, meats or vegetable in retail outlets.
Therefore, perishable items may be presented for sale, use or distribution as counter displays, refrigerated fruit, vegetable and flower stands, refrigerated retail displays for meats and processed foods, packaged and sealed dry goods such as grains, processed grains such as flour, manufactured pharmaceuticals, blood and blood products and organs for organ transplants, or any other approach when presented for harvesting, transportation, processing, packaging, displaying or selling. Similar or equivalent but unmentioned modes of treating any other oxygen perishable items are to be included.
Subjecting of perishable items to an open atmosphere in the presence of oxygen and particularly when at ambient or elevated temperatures causes the perishable items to lose freshness and texture, decay, produce objectionable odors, and become inedible, unsalable or unusable. To rectify this, means and methods have been sought to lessen the objectionable results and extend the useful life of perishable items. Most decay or spoilage of perishable items is the result of growth of aerobic microorganisms or pathogens including bacteria, fungi, viruses, which are of animal or vegetable origin.
U.S. Pat. No. 6,106,775, issued Aug. 22, 2001 discloses devices and methods for introducing humidity into an atmosphere. The device comprises an apertured shell containing an absorbent material inside which can absorb and retain water. Evaporation of water is enhanced by placing a mixture of sodium bicarbonate and acetylsalicylic acid (aspirin) on the absorbent material. The purpose is to humidify produce bins, refrigerated produce containers, cheese and meat refrigerators and containers of dry food, such as cookies and brown sugar.
Published U.S. Application 20010031298, published Oct. 18, 2001, is indirectly a continuation-in-part of U.S. Pat. No. 6,106,775, and teaches the use of aqueous compositions containing a combination of sodium bicarbonate and acetylsalicylic acid (aspirin) to maintain relatively high levels of carbon dioxide in the atmosphere of selected environments to prolong the shelf life of various perishable foods and products such as vegetables, fruits, meats, fish, seafood, dairy products and dry goods. The aqueous composition can be applied by directly bathing or showering a perishable product in the aqueous composition or indirectly using absorption devices that carry the aqueous compositions placed in close proximity to a perishable product.
Currently the favored means is by using suitable oxygen absorbers to prevent oxygen from destroying or rendering perishable items unsalable or useless. Most oxygen absorbers presently used are based on iron powder, iron oxides or iron salts which react with oxygen in the surrounding atmosphere causing the iron powder or salt to oxidize, further oxidize or rust. When all the iron has oxidized the oxygen absorbers are loaded and cease to function. The iron containing powder is packaged in plastic bags which are permeable to oxygen. The iron containing powder may be formulated with activated charcoal, and salts to further absorb oxygen or hasten its conversion to an iron oxide.
These oxygen absorbers are not edible and have limited life span when exposed to the atmosphere. They function best when used in a sealed or closed environment such as in dry pack canning but are not suitable for fresh produce such as fruits, vegetables, freshly cut and or packaged meats. In such situations, where oxygen may be present in the surrounding environment, iron based absorbers have limited utility. Further, iron oxygen absorbers often leave a metallic taste in produce, grains and other products where they have been utilized in a sealed environment for an extended period of time.
In view of the foregoing, there is a need for advancements in the art for compositions and methods providing innovative techniques for preserving oxygen perishable products. It would be particularly useful if such preservation compositions and techniques could be used at ambient or refrigerated conditions and be endothermic in nature to minimize or preserve ambient temperatures for the extended life of oxygen perishable products. It would also be advantageous to provide preservation systems and methods that are cost efficient and are safe for use with foods intended for animal and particularly human consumption. Any increase in the shelf life of oxygen perishable products, such as foods, could have great benefit for many entities involved in the relevant industries, including growers, transporters, retail outlets such as markets, food outlets, and, ultimately, consumers